Herman D. Wiser's U.S. Pat. No. 5,131,695, which is assigned to Chatleff Controls, Inc. of Buda, Tex., discloses and claims a connector assembly which contains (a) a connector body with a first end and a second end having a central channel and an internal annular sealing groove, said adaptor and external sealing groove being dimensioned relative to the connector body and internal sealing groove such that a portion of the adaptor and external groove are received within the central channel of the connector body, and the internal groove and the external groove mate to form a variable washer seal cavity, (b) a washer disposed within the variable seal cavity for forming a sealed connection when the body and adaptor are engaged, the adaptor having an annular stop surface thereon, said stop surface positioned such that it contacts a portion of the connector body after the washer has exceeded its maximum intended compression, and (c) means for movably connecting the connector body to the adaptor and selectively positioning the external sealing groove with respect to the internal sealing groove to thereby vary the compression of the washer within the variable seal cavity. The disclosure of this patent is hereby incorporated by reference into this specification.
U.S. Pat. No. 5,131,695 was reexamined, and reexamined patent B1 5,131,695 was issued on Jan. 18, 1994. The reexamined patent claimed a connector assembly similar to that claimed in U.S. Pat. No. 5,131,695 and additionally containing a generally cylindrical collar having internal threads adapted for engaging a threaded outer surface of the body, said collar also having an inwardly extending annular flange ring engaging a flange extending radially outward from the adaptor.
The reusable union coupling disclosed in U.S. Pat. Nos. 5,131,695 and B1 5,131,695 is being sold by Chatleff Controls, Inc. of Buda, Tex. This coupling is frequently used in refrigeration systems.
As is discussed in column 1 of U.S. Pat. No. 5,131,695, "Refrigeration systems may typically include several components, such as compressors, condensers, heat exchangers, and valves, which must be connected together in a way that effectively seals the interior of the refrigerant circulating system from the environment around it. Refrigerants, such as freon, which are introduced into such systems as the working fluid, are expensive, hazardous to the environment, and sometimes toxic . . . "
The Chatleff coupling, however, presents a problem: during its installation, it sometimes is damaged so that it ceases to function in its intended manner.
As is illustrated in design patent Des. 341,409, which is also assigned to Chatleff Controls, Inc, which depicts the Chatleff coupling, and which is hereby incorporated by reference into this specification, the Chatleff coupling is adapted to be used with a multiplicity of copper circuit tubes which are joined to the top of the coupling. These copper circuit tubes are conventionally attached to the top of the coupling by a silver brazing process in which temperatures in excess of 1,200 degrees Fahrenheit are often applied to the coupling body. This heat treatment affects the physical properties of the coupling body, effectively annealing it.
After the copper circuit tubes are joined to the coupling body, the coupling body is then joined to another device (such as, e.g., a condenser evaporator coil) by applying torque to it, typically with a wrench. Depending upon the size, strength, and energy of the person attaching the coupling, and the length of the wrench used, the amount of torque applied will vary within wide limits. Although the coupling body is designed to be torqued within specified given limits, these limits are often exceeded, especially when the person installing the fitting does not have a torque wrench readily accessible.
Disposed within the coupling body is a central passageway (see, e.g., channel 16 of U.S. Pat. No. 5,131,695) in which a movable piston is frequently disposed. Typically, the outside diameter of the piston is only from about 0.001 to about 0.003 inches smaller than the diameter of the channel. Thus, it does not require much distortion of the walls of the coupling body to cause such walls to impinge upon and affect the function of the movable piston.
Damage to the movable piston often will not be discovered until the coupling has been installed and the refrigeration system has been charged with "expensive", "hazardous", and/or "toxic" refrigerant fluid.
When concealed damage to the movable piston is discovered after installation of the coupling, it often requires a substantial amount of time and expense to remedy the problem. The are a substantial number of state and federal regulations governing the repair of devices containing refrigerants such as chlorofluorocarbons, hydrochlorofluorocarbons, and other regulated refrigerant materials. A licensed technician must evacuate the refrigeration system, remove the coupling, repair or replace the coupling and/or the movable piston within it, reconnect the coupling, charge the system with fresh refrigerant, dispose of the used refrigerant, and fill out whatever forms are necessary. It is desirable to avoid this tedious, time consuming, expensive process.
It is an object of this invention to provide a reusable union coupling which is substantially less likely than the coupling of U.S. Pat. No. 5,131,695 to be damaged during its installation.